1. Field of the Invention
The present invention relates to a sound-image position control apparatus which is suitable for use in the electronic musical instruments, audio-visual devices and the like so as to eventually perform the sound-image localization.
2. Prior Art
As the devices which offers the person the sound-broadened image, there are provided the stereo-chorus device, reverberation device and the like. Herein, the former one is designed to produce the sound of which phase is slightly shifted as compared to that of the original sound so that this phase-shifted sound and the original sound are alternatively produced from the left and right loud-speakers, while the latter one is designed to impart the reverberation effect to the sounds.
In addition, there is another device, called the panning device. This panning device is designed to provide the predetermined output-level difference between the sounds which are respectively produced from the left and right loud-speakers, resulting that the stereophonic effect or stereo-impressive image is applied to the sounds.
The above-mentioned stereo-chorus device or reverberation device can enlarge the sound-broadened image. However, there is a drawback in that the sound-distribution image which is sensed by the listener must become unclear when enlarging the sound-broadened image. Herein, the sound-distribution image is defined as a degree of discrimination in which the person who listens to the music from the audio device can specifically discriminate the sound of certain instrument from the other sounds. For example, when listening to the music played by the guitar and keyboard by the audio an device having a relatively good sound-distribution image control, the person can discriminate the respective sounds as if the guitar sound is produced from the predetermined left-side position, while the keyboard sound is produced from the predetermined right-side position (hereinafter, such virtual position will be referred to as the sound-image position). When listening to the music by use of the aforementioned stereo-chorus device or reverberation device, it is difficult for the person to clearly discriminate the sound-image positions.
In the panning device, the sound-image position must be fixed at the predetermined position disposed on the line connecting the left and right loud-speakers on the basis of the sound-image localization technique, resulting that the sound-broadened image cannot be substantially obtained. In other words, when simultaneously producing plural sounds each having a different sound-image position, the panning device merely functions to roughly mix up those sounds so that the clear sound-image positions cannot be obtained.
In the meantime, the panning device is frequently equipped with or built in the electronic musical instrument when simulating the sounds of the relatively large-scale instruments such as the piano, organ and vibraphone. In such instrument (e.g., piano), the sound-producing positions must be moved accompanied with the progression of notes, thus, the panning device functions to simulate such movement of the sound-producing positions.
However, the panning device also suffers from the aforementioned drawback. More specifically, the panning device can offer certain degree of panning effect when simulating the sounds, however, it is not possible to clearly discriminate the sound-image position of each of the sounds to be produced. In short, the panning device cannot perform the accurate simulation with respect to the discrimination of the sound-image positions.